This invention relates generally to tubular unions or quick coupling fittings used to assemble temporary tube and pipe assemblies and more particularly to the assembly of heavy tubular connections used for oil and gas well operations relating to wire-line wellhead set-ups that require lifting of the wellhead tubular riser while being attached to a down hole tubular string without removing or otherwise disturbing the wire-line cable located within the tubular string.
Tubular connection joints are generally made in several ways, i.e. welded, threaded, or flanged. Although each such connection joint may be considered as temporary due to the fact that the joints may be cut, unscrewed or unbolted, tubular joint connections that require frequent disassembly or orientation of the coupled members after assembly often resort to union type fittings. Such fittings provide some type of coupling member attached to each of the tubular members being joined, one or both of the coupling members having a sealing means, and the coupling members joined by a single threaded nut or collar member. This arrangement permits each tubular member to be rotated relative to its joining member and allows for a fast assembly or disassembly by simply rotating the single nut. The arrangement works well in most cases where there is no tensile loading placed on the joint. If a pulling force is placed on the joint, the threaded nut or collar securing the joint coupling members together most likely will fail since the load is applied directly to the threads. When setting up wire-line tubular risers connected to a wellhead in a manner known within the art as a free point riser set-up, whereby the riser is connected to the down hole tubing string, quick couplings or unions such Bowen(trademark) (trademark registered to Bowen Tool Corp.) type fittings may not be used, thereby requiring extensive setup time using threaded or flanged connections between tubular joints, valves etc.
This invention relates to a heavy, tubular, quick coupling used on oil and gas well tubing or pipe joints for allowing long strings of pipe, subsequently connected to quick coupled joints, to be lifted as a string, thereby applying tensile loading on the quick coupled joints. Both interior and exterior locking arrangements are disclosed that utilize twist-locking elements secured in position by a locking washer and cap nut. Arrangements also are disclosed illustrating how the locking coupling is used for fast setup of wire-line riser strings and utilizing multiple valve assemblies.